Re: [PATCH v3 09/13] mm: zswap: Modify struct crypto_acomp_ctx to be configurable in nr of acomp_reqs.

Johannes Weiner
2024-11-07T17:21:02Z

On Wed, Nov 06, 2024 at 11:21:01AM -0800, Kanchana P Sridhar wrote:
> Modified the definition of "struct crypto_acomp_ctx" to represent a
> configurable number of acomp_reqs and the required number of buffers.
>
> Accordingly, refactored the code that allocates/deallocates the acomp_ctx
> resources, so that it can be called to create a regular acomp_ctx with
> exactly one acomp_req/buffer, for use in the the existing non-batching
> zswap_store(), as well as to create a separate "batching acomp_ctx" with
> multiple acomp_reqs/buffers for IAA compress batching.
>
> Signed-off-by: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
> ---
> mm/zswap.c | 149 ++++++++++++++++++++++++++++++++++++++---------------
> 1 file changed, 107 insertions(+), 42 deletions(-)
>
> diff --git a/mm/zswap.c b/mm/zswap.c
> index 3e899fa61445..02e031122fdf 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -143,9 +143,10 @@ bool zswap_never_enabled(void)
>
> struct crypto_acomp_ctx {
> struct crypto_acomp *acomp;
> - struct acomp_req *req;
> + struct acomp_req **reqs;
> + u8 **buffers;
> + unsigned int nr_reqs;
> struct crypto_wait wait;
> - u8 *buffer;
> struct mutex mutex;
> bool is_sleepable;
> };
> @@ -241,6 +242,11 @@ static inline struct xarray *swap_zswap_tree(swp_entry_t swp)
> pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
> zpool_get_type((p)->zpool))
>
> +static int zswap_create_acomp_ctx(unsigned int cpu,
> + struct crypto_acomp_ctx *acomp_ctx,
> + char *tfm_name,
> + unsigned int nr_reqs);

This looks unnecessary.

> +
> /*********************************
> * pool functions
> **********************************/
> @@ -813,69 +819,128 @@ static void zswap_entry_free(struct zswap_entry *entry)
> /*********************************
> * compressed storage functions
> **********************************/
> -static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node)
> +static int zswap_create_acomp_ctx(unsigned int cpu,
> + struct crypto_acomp_ctx *acomp_ctx,
> + char *tfm_name,
> + unsigned int nr_reqs)
> {
> - struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node);
> - struct crypto_acomp_ctx *acomp_ctx = per_cpu_ptr(pool->acomp_ctx, cpu);
> struct crypto_acomp *acomp;
> - struct acomp_req *req;
> - int ret;
> + int ret = -ENOMEM;
> + int i, j;
>
> + acomp_ctx->nr_reqs = 0;
> mutex_init(&acomp_ctx->mutex);
>
> - acomp_ctx->buffer = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
> - if (!acomp_ctx->buffer)
> - return -ENOMEM;
> -
> - acomp = crypto_alloc_acomp_node(pool->tfm_name, 0, 0, cpu_to_node(cpu));
> + acomp = crypto_alloc_acomp_node(tfm_name, 0, 0, cpu_to_node(cpu));
> if (IS_ERR(acomp)) {
> pr_err("could not alloc crypto acomp %s : %ld\n",
> - pool->tfm_name, PTR_ERR(acomp));
> - ret = PTR_ERR(acomp);
> - goto acomp_fail;
> + tfm_name, PTR_ERR(acomp));
> + return PTR_ERR(acomp);
> }
> +
> acomp_ctx->acomp = acomp;
> acomp_ctx->is_sleepable = acomp_is_async(acomp);
>
> - req = acomp_request_alloc(acomp_ctx->acomp);
> - if (!req) {
> - pr_err("could not alloc crypto acomp_request %s\n",
> - pool->tfm_name);
> - ret = -ENOMEM;
> + acomp_ctx->buffers = kmalloc_node(nr_reqs * sizeof(u8 *),
> + GFP_KERNEL, cpu_to_node(cpu));
> + if (!acomp_ctx->buffers)
> + goto buf_fail;
> +
> + for (i = 0; i < nr_reqs; ++i) {
> + acomp_ctx->buffers[i] = kmalloc_node(PAGE_SIZE * 2,
> + GFP_KERNEL, cpu_to_node(cpu));
> + if (!acomp_ctx->buffers[i]) {
> + for (j = 0; j < i; ++j)
> + kfree(acomp_ctx->buffers[j]);
> + kfree(acomp_ctx->buffers);
> + ret = -ENOMEM;
> + goto buf_fail;
> + }
> + }
> +
> + acomp_ctx->reqs = kmalloc_node(nr_reqs * sizeof(struct acomp_req *),
> + GFP_KERNEL, cpu_to_node(cpu));
> + if (!acomp_ctx->reqs)
> goto req_fail;
> +
> + for (i = 0; i < nr_reqs; ++i) {
> + acomp_ctx->reqs[i] = acomp_request_alloc(acomp_ctx->acomp);
> + if (!acomp_ctx->reqs[i]) {
> + pr_err("could not alloc crypto acomp_request reqs[%d] %s\n",
> + i, tfm_name);
> + for (j = 0; j < i; ++j)
> + acomp_request_free(acomp_ctx->reqs[j]);
> + kfree(acomp_ctx->reqs);
> + ret = -ENOMEM;
> + goto req_fail;
> + }
> }
> - acomp_ctx->req = req;
>
> + /*
> + * The crypto_wait is used only in fully synchronous, i.e., with scomp
> + * or non-poll mode of acomp, hence there is only one "wait" per
> + * acomp_ctx, with callback set to reqs[0], under the assumption that
> + * there is at least 1 request per acomp_ctx.
> + */
> crypto_init_wait(&acomp_ctx->wait);
> /*
> * if the backend of acomp is async zip, crypto_req_done() will wakeup
> * crypto_wait_req(); if the backend of acomp is scomp, the callback
> * won't be called, crypto_wait_req() will return without blocking.
> */
> - acomp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
> + acomp_request_set_callback(acomp_ctx->reqs[0], CRYPTO_TFM_REQ_MAY_BACKLOG,
> crypto_req_done, &acomp_ctx->wait);
>
> + acomp_ctx->nr_reqs = nr_reqs;
> return 0;
>
> req_fail:
> + for (i = 0; i < nr_reqs; ++i)
> + kfree(acomp_ctx->buffers[i]);
> + kfree(acomp_ctx->buffers);
> +buf_fail:
> crypto_free_acomp(acomp_ctx->acomp);
> -acomp_fail:
> - kfree(acomp_ctx->buffer);
> return ret;
> }
>
> -static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node)
> +static void zswap_delete_acomp_ctx(struct crypto_acomp_ctx *acomp_ctx)
> {
> - struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node);
> - struct crypto_acomp_ctx *acomp_ctx = per_cpu_ptr(pool->acomp_ctx, cpu);
> -
> if (!IS_ERR_OR_NULL(acomp_ctx)) {
> - if (!IS_ERR_OR_NULL(acomp_ctx->req))
> - acomp_request_free(acomp_ctx->req);
> + int i;
> +
> + for (i = 0; i < acomp_ctx->nr_reqs; ++i)
> + if (!IS_ERR_OR_NULL(acomp_ctx->reqs[i]))
> + acomp_request_free(acomp_ctx->reqs[i]);
> + kfree(acomp_ctx->reqs);
> +
> + for (i = 0; i < acomp_ctx->nr_reqs; ++i)
> + kfree(acomp_ctx->buffers[i]);
> + kfree(acomp_ctx->buffers);
> +
> if (!IS_ERR_OR_NULL(acomp_ctx->acomp))
> crypto_free_acomp(acomp_ctx->acomp);
> - kfree(acomp_ctx->buffer);
> +
> + acomp_ctx->nr_reqs = 0;
> + acomp_ctx = NULL;
> }
> +}
> +
> +static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node)
> +{
> + struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node);
> + struct crypto_acomp_ctx *acomp_ctx;
> +
> + acomp_ctx = per_cpu_ptr(pool->acomp_ctx, cpu);
> + return zswap_create_acomp_ctx(cpu, acomp_ctx, pool->tfm_name, 1);
> +}
> +
> +static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node)
> +{
> + struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node);
> + struct crypto_acomp_ctx *acomp_ctx;
> +
> + acomp_ctx = per_cpu_ptr(pool->acomp_ctx, cpu);
> + zswap_delete_acomp_ctx(acomp_ctx);
>
> return 0;
> }

There are no other callers to these functions. Just do the work
directly in the cpu callbacks here like it used to be.

Otherwise it looks good to me.